One could envision that the normal ride suspension leveling valves being a single design in the front will reach a compromise position without putting any twisting forces on the frame given it will add or subtract air from the four front airsprings uniformly. The rear leveling valves will attempt to offset some amount of side tilt but they are limited in how much compensation they can achieve, especially on the front of the coach, given they are acting on just the rear axle air springs which are all out board. So the coach is fairly uniformly resting on 8 or 10 air springs.
My guess is that the designers felt that the maximum amount of frame twist that could be created was less for the ride suspension leveling valve system due to its configuration than either the full air leveling system or the hydraulic system which has more range of movement and therefor the ability to put more force on one quadrant of the coach frame vs another.
I think it is range of motion for each system that you have to think about and the worst torque on the frame comes when corners are at the extremes of lift and fall range.
The aired up ride suspension I believe would have less range of movement. It is really not about whether you are level or not, it is about how much force and twist was put on the frame to achieve level. Did the required leveling forces distort the slide openings?
I thinco Monaco says aired up resting on 8 or 10 airbags within the range of the over the road leveling system should have limited frame twist enough that the slides will work properly. Most all the problems with body torque seems to occur in the front with windshields popping and large slides rubbing. The front over the road air leveling system does not compensate for side to side offeset at all by design. I'm not the designer but this makes sense to me so I always let the slides out before I dump air and level and always air up before I bring them in.
Later Ed
